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Cant find proper method or idea how to...

P: n/a
Hi all.

Got 1 question and it's troubling me totally. I please someone to
answer me.

I'm building one project over php/javascript and it's not problem to
load practically anything but 1 thing is spending my nerves totally.

Question is:

Is it possible somehow to retrieve data in real time mode? I just
don't wan to use setTimeout or setInterval methods. Something like
data.onUpdate or something like that hehe :)

Thanks for helpin me out.

Cheers!
Sep 21 '08 #1
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6 Replies


P: n/a
SAM
Nevio a écrit :
Hi all.

Got 1 question and it's troubling me totally. I please someone to
answer me.

I'm building one project over php/javascript and it's not problem to
load practically anything but 1 thing is spending my nerves totally.

Question is:

Is it possible somehow to retrieve data in real time mode? I just
don't wan to use setTimeout or setInterval methods. Something like
data.onUpdate or something like that hehe :)

Thanks for helpin me out.
and with some context ?

(when does the datas have to be updated ?
and where the new datas are ?
and where to display these last ones ?)

Ajax ?
Js :
====
var data = 'hello ';

html :
======
your name : <input on change="alert(data+this.value);">
--
sm
Sep 21 '08 #2

P: n/a
On 2008-09-21 12:23, Nevio wrote:
Is it possible somehow to retrieve data in real time mode? I just
don't wan to use setTimeout or setInterval methods. Something like
data.onUpdate or something like that hehe :)
I assume that by "retrieving data" you mean fetching data from a server
with JavaScript, and that you would like data updates to be pushed from
the server instead of pulled. Would this be of any help to you?

http://en.wikipedia.org/wiki/Comet_(programming)

It's possible, but implementation is a little tricky (on both ends), and
not an easy task for beginners.
- Conrad
Sep 21 '08 #3

P: n/a
On Sep 21, 12:23 pm, Nevio <nve...@gmail.comwrote:
>
Question is:

Is it possible somehow to retrieve data in real time mode? I just
don't wan to use setTimeout or setInterval methods. Something like
data.onUpdate or something like that hehe :)

Because a server can't initiate a transfer, one would initially think
that there's no way, but there is, yes, and a quite good one, in fact:

You just need to make sure that there's *always* a (one) pending XHR.
Upon entering (onload) of the page:

1.- Post the XHR that will receive the 'real time' data.
2.- This XHR will complete with either a timeout or because some 'real
time' data has arrived.
3.- Post inmediatly after completion ('2') another XHR (goto '1').

As you can see, whenever/if the server has some 'real time' data to
send to the client, it can do so through the currently open/pending
XHR.

The latest firefoxes can have up to six different, concurrent XHRs
ongoing, most other browsers can have up to 4. I don't know about IE,
though.
See http://preview.tinyurl.com/6mm5tm

--
Jorge.
Sep 21 '08 #4

P: n/a
Jorge <jo***@jorgechamorro.comwrites:
On Sep 21, 12:23 pm, Nevio <nve...@gmail.comwrote:
>>
Question is:

Is it possible somehow to retrieve data in real time mode? I just
don't wan to use setTimeout or setInterval methods. Something like
data.onUpdate or something like that hehe :)


Because a server can't initiate a transfer, one would initially think
that there's no way, but there is, yes, and a quite good one, in fact:

You just need to make sure that there's *always* a (one) pending XHR.
Upon entering (onload) of the page:

1.- Post the XHR that will receive the 'real time' data.
2.- This XHR will complete with either a timeout or because some 'real
time' data has arrived.
3.- Post inmediatly after completion ('2') another XHR (goto '1').
Actually, you don't need XHR at all. It's easier to just push a <script>
tag to a hidden frame. That way, you don't need to repeat requests; you
just keep appending to a single reply (and you can do that from a
different server than your "main" page).

--
Joost Diepenmaat | blog: http://joost.zeekat.nl/ | work: http://zeekat.nl/
Sep 21 '08 #5

P: n/a
On Sep 21, 10:23*pm, Joost Diepenmaat <jo...@zeekat.nlwrote:
>
Actually, you don't need XHR at all. It's easier to just push a <script>
tag to a hidden frame. That way, you don't need to repeat requests; you
just keep appending to a single reply (and you can do that from a
different server than your "main" page).
Sounds good, but I don't get it or I'm missing something: you request
a script, but it's not until it has been 'completely' received that it
executes (right?), it holds the wanted data, and it has to re-request
another script ?

If so, there are -as well- going to be multiple requests... or not ?

And what about security matters ? What if somebody manages to inject
one of his own scripts instead of yours ? Because one thing is getting
the wrong data and another different one is letting the door open to
code injection attacks.

--
Jorge.
Sep 21 '08 #6

P: n/a
On Sep 21, 11:03*pm, Jorge <jo...@jorgechamorro.comwrote:
On Sep 21, 10:23*pm, Joost Diepenmaat <jo...@zeekat.nlwrote:
Actually, you don't need XHR at all. It's easier to just push a <script>
tag to a hidden frame. That way, you don't need to repeat requests; you
just keep appending to a single reply (and you can do that from a
different server than your "main" page).

Sounds good, but I don't get it or I'm missing something: you request
a script, but it's not until it has been 'completely' received that it
executes (right?), it holds the wanted data, and it has to re-request
another script ?

If so, there are -as well- going to be multiple requests... or not ?

And what about security matters ? What if somebody manages to inject
one of his own scripts instead of yours ? Because one thing is getting
the wrong data and another different one is letting the door open to
code injection attacks.

--
Jorge.
Oh... thanks guys for this! I will try to do it over pending XHR but
kinda
somehow i see flex ( AS ) as currently the best solution. I'm doing
some huge chat system
and kinda better is to just start with AS as I think. But for
notifiers and rest of it
ill use this pending XHR methods. Thanks Jorge and rest of you who
wanted to help me out.

I dun ever ever ever use iframe. If I need it, I use div instead lol.
That thing is old and full of security holes as I know.

Cheers
Sep 21 '08 #7

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